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Maker Pro

Help Needed: Building 18V Power Supply for Power Tools


Aug 6, 2015
Aug 6, 2015
Updated drawing, correcting some confusing elements, and accounting for my new 15V transformer.

Hope this helps others out there trying to do the same thing as me..

BTW, my total cost, including some 'luxury' additions was less than $200, cheaper than buying 2 new batteries, and MUCH longer-lasting..

Hello Stevee2002, I have little to none knowledge of electronics and very basic for electricity. I have been playing with some laptop AC adapters but none has made the Ryobi tools to work, they spin fast once and then die.
I would like to try your method but no sure what to buy.
Don't know if live links are allowed on the forum but here is what I understand I will need: (qty 2) (qty 3) (qty 1)

Some cable, solder follwing your Wiring.Diagram.Rev2.pdf and connect the output to my empty battery terminals.

Can you please confirm? I had 4 batteries and none holds charge no more. Don't want to spend more money on batteries that last 1 summer project.